Sum-frequency-based photon-number-resolving detector for telecom wavelengths

The use of C-band wavelengths in the field of quantum communication has grown significantly, driving the need for versatile detection solutions, especially in the low intensity domain. Among the desirable features for such detectors, photon-number-resolving (PNR) capability is particularly valuable, since it can offer new possibilities for enhancing security of communication protocols. In this paper, we present the implementation of a receiver that combines low-cost PNR detectors with nonlinear optical interactions to achieve sensitivity at telecom wavelengths. In particular, we use this receiver to characterize the Poissonian nature of a femtosecond source at 1.5 μm, produced via white light continuum generation followed by a single-stage amplification process. The obtained results encourage the exploitation of such a detector in more complex schemes.